Unless otherwise indicated herein, the description provided in this background section is not itself prior art to the claims and is not admitted to be prior art by inclusion in this section.
A wireless communication system provided by a wireless service provider or “carrier” may include one or more cell sites that define coverage in which the carrier may serve mobile terminals such as cell phones, wirelessly-equipped computers, tracking devices, or the like. In particular, the carrier may operate or otherwise provide one or more base stations (also known as access nodes, access points, eNodeBs, and by other names), each having an antenna structure and associated equipment arranged to provide coverage areas such as cells and sectors in which to serve mobile terminals. Each base station may then include or be communicatively linked with network infrastructure that provides connectivity with a packet-switched network such as the Internet.
When a mobile terminal enters into coverage of a carrier's cell site, the mobile terminal may engage in an attachment process through which the terminal registers to be served by the carrier in that cell site. For instance, the mobile terminal may transmit an attach request to the base station of the cell site, and the associated network infrastructure may then authenticate and authorize the mobile terminal for service. Further, as part of this attachment process or as a separate process, the network infrastructure may also assign to the mobile terminal an Internet Protocol (IP) address that the mobile terminal can use to engage in packet-data communication on the packet-switched network. Once the mobile terminal is thus attached and has an assigned IP address, the mobile terminal may then engage use that IP address to communicate via the cell site and network infrastructure with other entities.
In general, a mobile terminal may subscribe to be served by a particular carrier known as the terminal's “home carrier.” For instance, an owner or operator of the mobile terminal may enter into a subscription agreement with the carrier, establishing that the carrier will provide the mobile terminal with wireless communication service in exchange for payment of specified fee. When the mobile terminal enters into coverage of a cell site provided by its home carrier, the mobile terminal then attach via that cell site and acquire an IP address to facilitate packet-data communication as noted above. In particular, the mobile terminal may transmit an attach request to the base station of the home carrier's cell site, and network infrastructure operated by the home carrier may then authenticate and authorize the mobile terminal for service. Further, as part of that attachment process or separately, the home carrier's network infrastructure may assign an IP address to the mobile terminal for use by the mobile terminal to engage in packet-data communication. The mobile terminal may then use that assigned IP address to communicate on the packet-switched network, via the home carrier's cell site and the home carrier network infrastructure.
Although a mobile terminal's home carrier may strive to offer wireless coverage throughout a region, however, the home carrier may not actually operate or otherwise provide cell sites in all locations throughout the region. To fill in gaps where the home carrier does not operate or otherwise provide its own cell sites, the home carrier may enter into roaming agreements with other carriers, referred to as “roaming partners” or “roaming carriers.” Under a roaming agreement, a roaming carrier may agree to have its cell sites serve the home carrier's subscriber terminals and to provide connectivity with the home carrier's network infrastructure so that the home carrier can authenticate and authorize the subscriber terminals and the home carrier's network infrastructure can provide the subscriber terminals with packet-data network connectivity. In accordance with the roaming agreement, the roaming carrier may then report such usage to the home carrier and may charge the home carrier for the usage. And the home carrier may pass that charge along to the service accounts of the subscriber terminals.
With such an arrangement, when a mobile terminal enters into coverage of a roaming carrier's cell site, the mobile terminal may attach via that roaming carrier's cell site and may then engage in packet data communication served by the home carrier. In particular, the mobile terminal may transmit an attach request to the roaming carrier's cell site, and, because the mobile terminal is a subscriber of the home carrier, the roaming carrier's network infrastructure may responsively signal to the home carrier's network infrastructure. The home carrier's network infrastructure may then authenticate and authorize the mobile terminal for service and, as part of that attachment process or separately, may assign an IP address to the mobile terminal for use by the mobile terminal to engage in packet-data communication. And the mobile terminal may then use that home-carrier assigned IP address to communicate on the packet-switched network, via the roaming carrier's cell site and the home carrier network infrastructure.